1. Field of the Invention
The present invention generally relates to the removal of unwanted aquatic plant material and/or other debris from lake bottoms and, more particularly, is concerned with a lake bottom plant gathering apparatus with improved actuation and cleaning of its plant raking mechanism.
2. Description of Problems and the Prior Art
Aquatic plants tend to grow in lakes throughout the United States and other parts of the world. Nutrients in the water of many lakes settle at the bottoms and provide nourishment for plant growth. In shallow areas, plants can grow out of control and make the water unsuitable for swimming, fishing or boating and can choke off other aquatic life. Herbicides have been used to combat this problem of rapid aquatic plant growth, but certain of them have proven unsuitable because of harmful effects on fish and other sensitive aquatic life.
Another problem sometimes encountered with the bottoms of lakes and rivers is other debris such as branches of trees, and discarded bottles and cans; such debris is potentially dangerous to humans wading or walking along the bottom.
Various devices have been developed to address the need for removing plants both on ground and below water. One example is the two-wheeled hay rake used by farmers years ago. This device involved a two-wheeled rake with tines that hung down between the wheels and was pulled by a team of horses or a tractor. As hay would accumulate under the tines, a human operator riding along would operate a lever to raise the tines up to thereby drop the load of hay. The operator would then return the tines back to the lowered position to gather up more hay as the device moved along. Up until the present, however, this two-wheeled rake has not been adapted for use under water. Other representative examples of devices used on ground are disclosed in U.S. Pat. No. 5,261,218 to Jones et al. and U.S. Pat. No. 5,287,935 to Foeller.
Many devices have also been developed specifically to provide for the removal of aquatic plant growth. Tug or boat dredges have been used for the harvesting of sea weed and the like. Such dredges generally have a leading cutting edge that is adapted to sever the material to be harvested from the ocean or lake bottom and a receptacle to retain the harvested material. But these dredges are meant for use in large bodies of water and are therefore not suitable for use in lakes or ponds that are too small for large boats.
Other devices have been developed in response to the need for removing aquatic plant growth from small bodies of water or from shallow areas of large bodies of water. While the common rigid yard rake with short, rigid tines and a rigid transverse bar atop the tines has been used for this purpose, it is an inefficient and time consuming way to remove and collect aquatic plants. Devices have therefore been developed that utilize a cutting edge or rake in combination with a variety of other techniques to guide the devices over lake or pond bottoms for the removal and collection of aquatic plants. Representative examples of these devices are disclosed in U.S. Pat. No. 3,863,237 to Doerr, U.S. Pat. No. 4,137,693 to Thompson et al., U.S. Pat. No. 4,696,149 to Hawk, U.S. Pat. No. 4,768,331 to Jones, U.S. Pat. No. 4,852,337 to Peterson, U.S. Pat. No. 5,074,105 to Roth and U.S. Pat. No. 5,146,997 to Korin.
The Doerr patent discloses a device with a leading cutting edge and a receptacle for the cut plants. While this device may seem simple, it lacks efficiency as the receptacle must be raised from the water and emptied each time it fills with plant stalks. Also, cutting edges tend only to sever plant stalks rather than remove both the plants and their roots as rake teeth or tines are more likely to do.
The Thompson patent discloses a motor-powered device with a pair of drive wheels that moves a rake with teeth backward and forward for the removal of aquatic plants. The problem with this device is that it is only adapted to be mounted on a beach or shoreline of a lake.
The Hawk patent discloses a device with a floating hull and pivotally attached boom which drags a transverse bar with a plurality of tines through muck to loosen and remove the roots of aquatic plants. A mesh scoop then collects plants that rise to the surface of the water. This device, however, is elaborate and complex, and does not have a tine cleaning mechanism.
The Jones patent discloses a device having a frame with teeth that removes aquatic plants and drags them to a central collection site on shore. A rope or chain is used to pull the rake out and in from the water. While this device may seem simple, it lacks efficiency as the teeth may become cluttered with plant stalks and thus fall to operate properly until the teeth are cleaned of debris.
The Peterson patent discloses a device with improved raking teeth having a relatively flexible and resilient filament extending between and loosely through the tines to distribute stress among the teeth. The problem with this arrangement is that it is complex and does not have a tine cleaning mechanism.
The Roth patent discloses a device having a lake rake operated by an articulated-boom hoist attached to a motorized vehicle. A rake float is used to transport the rake a select distance from the vehicle where the rake is then dropped to the lake bottom and pulled back toward the vehicle. The hoist then lifts the rake and then tilts and shakes it appropriately to cause accumulated plants to drop from it so as to permit the process to repeat itself. Although this device functions to gather and dump accumulated plant material, the overall process is nevertheless complex and does not have a rake cleaning mechanism.
The Korin patent discloses a device with two units, one land-based and the other submersible. The land-based unit has an engine that runs a hydraulic pump that drives a hydraulic motor on the submersible unit by way of an elongated hose. The submersible unit also includes a rotatable drum with tines for grubbing aquatic plants. Like other mentioned devices, however, this device does not have a tine cleaning mechanism and is complex.
Consequently, a need still exists for a simple lake rake having a tine cleaning mechanism for the efficient removal of unwanted aquatic plants and their roots from small or shallow bodies of water.